Alanxtl opened a new issue, #3431:
URL: https://github.com/apache/dubbo-go/issues/3431
## Problem
In `cluster/loadbalance/consistenthashing/selector.go`, `newSelector` parses
the configured `hash.arguments` values into `selector.argumentIndex`:
```go
selector.argumentIndex = append(selector.argumentIndex, i)
```
However, `toKey` currently iterates with `range` over the slice and uses the
loop index instead of the configured value:
```go
for i := range c.argumentIndex {
if i >= 0 && i < len(args) {
_, _ = fmt.Fprint(&sb, args[i])
}
}
```
This means `methods.<method>.hash.arguments=1` still uses `args[0]`, because
`i` is the position in `argumentIndex`, not the configured argument index.
## Example
With:
```text
methods.echo.hash.arguments=1
args = []any{"tenantA", 42}
```
Expected key should be based on `args[1]`, i.e. `"42"`.
Actual key is based on `args[0]`, i.e. `"tenantA"`.
This can make consistent hashing route by the wrong request argument and may
produce different routing behavior from the configured intent and from Java
Dubbo's implementation.
## Suggested fix
Use the configured argument index values when building the key:
```go
for _, i := range c.argumentIndex {
if i >= 0 && i < len(args) {
_, _ = fmt.Fprint(&sb, args[i])
}
}
```
It would also be useful to add regression tests for non-zero
`hash.arguments`, for example `hash.arguments=1` with `[]any{"ignored", 123}`
should produce key `"123"`.
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